1. Field of Invention
This invention relates to substituted polybenzimidazole polymers and processes for their production. More particularly the invention relates to N-substituted alkyl, alkenyl or aryl substituted polybenzimidazole polymers and processes for their production.
2. Prior Art
Polybenzimidazoles are a known class of heterocyclic polymers which are characterized by a high degree of thermal and chemical stability. Processes for their production are disclosed in U.S. Re. 26,065 and U.S. Pat. Nos. 3,313,783, 3,509,108, 3,555,389, 3,433,772, 3,408,336, 3,549,603, 3,708,439, 4,154,919 and 4,312,976. (All patents enumerated herein are incorporated by reference).
Although polybenzimidazole polymers are generally more resistant to chemical reaction than other types of polymers, such as cellulose acetate polymers, reactions at the imidazole nitrogen-hydrogen bond on the polybenzimidazole polymer will occur under certain condition, thereby adversely affecting the performance of the polybenzimidazole polymer.
One method of reducing this reactivity is by replacing the imidazole hydrogen with a less reactive substituent to produce a substituted polybenzimidazole polymer. For example, U.S. Pat. No. 4,579,915 discloses a substituted polybenzimidazole polymer wherein the imidazole hydrogen is replaced by an aromatic substituent corresponding to the formula: ##STR1## where R is nitro , cyano or trifloromethyl and R' is hydrogen, alkyl, nitro, cyano or trifloromethyl. In addition, U.S. Pat. No. 4,377,546 discloses a phenyl substituted polybenzimidazole polymer. However, neither patent discloses the instant process for production of N-substituted polybenzimidazole polymers.
U.S. Pat. No. 3,943,125 discloses a vast array of substituted tetramino, heterocyclic compounds useful in the preparation of substituted polybenzimidazole polymers. However, the process for production of the substituted polybenzimidazole polymers disclosed in the '125 patent is significantly different from that disclosed in the instant invention.
U.S. Pat. No. 3,518,234 discloses aryl substituted polybenzimidazole polymers but fails to disclose the instant process for the production of N-substituted polybenzimidazole polymers.
U.S. Pat. Nos. 3,578,644 and 4,549,388 disclose processes for the production of hydroxyl modified polybenzimidazoles, but fail to disclose N-alkyl, N-aryl or N-alkenyl substituted polybenzimidazole polymers or a process for their production.
Accordingly, it is an object of the present invention to prepare N-substituted polybenzimidazole polymers.
It is a further object of this invention to prepare N-substituted polybenzimidazole polymers that exhibit a high degree of chemical and thermal stability.
It is a still further object of this invention to prepare N-substituted polybenzimidazole polymers directly from unsubstituted polybenzimidazole polymers.
It is an additional object of this invention to prepare N-substituted polybenzimidazole polymers using an alkali hydride to generate polybenzimidazole anions which are subsequently reacted with a substituted methyl halide to generate N-substituted polybenzimidazole polymers.
These and other objects, as well as the scope, nature, and utilization of the process will be apparent to those skilled in the art from the following description and appended claims.